HOW DOES TEMPERATURE AFFECT CATALASE ENZYMES?

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Introduction

HOW DOES TEMPERATURE AFFECT CATALASE ENZYMES? Aim. To investigate the affect of temperature on catalase enzyme activity, using a potato as a catalyst. The source of catalase is in the potato cells. Theory. I have done some research to find out about enzymes in general and about catalase. Enzyme is a protein molecule that speeds up chemical reactions in all living things. Without enzymes, these reactions would occur too slowly or not at all, and no life would be possible. Many enzymes break down complex substances into simpler ones. Others build complex compounds from simple ones. Most enzymes remain in the cells where they were formed, but some enzymes work elsewhere. For example, the pancreas secretes the enzyme lipase, which travels to the small intestine, where it breaks down fats. An enzyme's structure can easily be destroyed by heat, or PH. For example, scientists believe that a high body temperature, such as 42 �C, may cause death because the heat makes vital enzymes inactive. Enzymes have many uses in addition to their natural functions in the body. Manufacturers use enzymes in making a wide variety of products. For example, some detergents contain enzymes that break down proteins or fats that cause stains. Enzymes are also used in the manufacture of antibiotics, beer, bread, cheese, coffee, sugars, vinegar, vitamins, and many other products. Doctors use medicines containing enzymes to help clean wounds, dissolve blood clots, relieve certain forms of leukaemia, and check allergic reactions to penicillin. Doctors also diagnose some diseases by measuring the amount of various enzymes in blood and other body fluids. Such diseases include anaemia, cancer, leukaemia, and heart and liver ailments. All living cells make enzymes, but enzymes are not alive. Enzyme molecules function by altering other molecules. Enzymes combine with the altered molecules to form a complex molecular structure in which chemical reactions take place. Enzymes do not undergo any permanent chemical change of their own. The enzyme, which remains unchanged, then separates from the product of the reaction. ...read more.

Middle

IMPORTANT NOTE: check that the bottle top of gas syringe fits selected conical flask. 7. Grate a potato using a grater on a tile. The potato should be grated on the medium sized grater. The potato should not be in contact with the table in case it is mixed with any other substances already on the table. 8. Leave this grated potato in a large beaker. 9. Measure out 5g of grated potato and put it in the conical flask using a spatula. 10. Using the measuring cylinder, measure 30ml of hydrogen peroxide. 11. When pouring hydrogen peroxide into the conical flask, make sure you don't spill any of it on your hand. If you happen to accidentally spill some, wash it off quickly under cold, running water. 12. Get the stop watch ready. 13. Reset the timer. 14. Pour in the 20ml of hydrogen peroxide into the conical flask. 15. Push the gas syringe into the top of the conical flask instantly and start the stopwatch immediately. 16. Repeat this with six other temperatures for the hydrogen peroxide to get more accurate results and also to make it a fair test. The different temperatures should be 0�C, 10�C, 20�C, 30�C, 40�C and 50�C. So we can see which temperature the enzymes work best at. 17. For each experiment, take down the results after every 30 seconds. Below is a diagram show how the experiment should be presented. Safety It is vital that while I am doing this experiment I am safe, the environment around is safe as well as people around me so I have made a list of safety precautions that I will take. 1. Wear safety goggles at all times to protect my eyes. 2. Keep my fingers away when grating the potato to avoid harming my fingers. 3. Not run with equipment especially equipments made of glass e.g. beakers. 4. ...read more.

Conclusion

I also think it would have been better if I had used the same potato from the whole experiment but was unable to due to the time restrictions. I had to conduct the experiment over a number of days and could not therefore use the same potato. This is a source of error because the concentration of catalase in the potatoes may have been different which may have produced an inconsistent rate of reaction. This might be one of the reasons in which my results were inaccurate. To remove this problem, I could repeat the experiment not only with three readings at each temperature, but also with three different potatoes, which would provide an even more accurate reading, as I could calculate an average. I would also carry out more experiments with a range of 5�C. I would do 0�C-70�C. By 70�C the enzyme would have denature. I would have carried out more experiments because this would give me more results and allow me to plot a more accurate graph. Also, it would be easier to tell when the enzyme got to the optimum temperature and denaturing point. So next time I would do all the things below to ensure even more accurate results; * Tighten the bung on the flask. * Use a good gas syringe (not too tight or loose) * Use the same equipments apart from the flask. * Do all the experiments on the same day using the same potato. * Use three different potatoes for each of the experiments so; I could calculate an even better average. * Make sure the water bath is working. * Carry out more experiment, with a temperature range of 5�C. Conclusion To summarize I found out that enzymes work fastest at 10�C even though according to my theory it should be 40�C. I also found out that it is correct about how the enzyme denatures after 40�C. So enzyme activity is affected by temperature. The optimum temperature for enzymes should be 40�C, and after this they should not work well as they are denatured. Aysha Sattar, 10b, 10/12/03 1 ...read more.

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